1. Field of the Invention
The present invention relates to the field of random number generators and more specifically to random number generators formed in an integrated circuit.
2. Discussion of the Related Art
The quality of a random generator is measured by the quality of its random character, that is, the generator's equiprobability to output any number.
Currently, random generators are, when designed, generally tested on a characterization batch enabling checking the quality of the random character. This quality of the random character is however not tested for each manufactured chip. At the end of the manufacturing, a functional test of the chip, but not of the random character's reliability, is generally performed.
Random generators are often used in algorithmic processing applications involving secret keys, and especially to mask the keying of these secret keys by the algorithms. The quality of the random character is of major importance in this type of application since this conditions the security of the data handling process.
Further, random generators, even if they operate properly at the end of the manufacturing, may be sensitive to drifts. Indeed, like any function implemented by an integrated circuit, the random generator may especially be sensitive to heat differences which are then likely to condition the quality of the random character.
It would thus be desirable to be able to validate the quality of a random character of an integrated generator in a chip.